Pin test runner to Ubuntu 18 to un-break CI (#24715)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c674c5d606c546d2957175476eec0bb005e26efb..ef54865ed964c7b4e106d9274370c64876162964 100644 (file)
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -127,7 +127,7 @@ jobs:
 
   build_ubuntu:
     name: 'Ubuntu'
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
     needs: check_source
     if: needs.check_source.outputs.run_tests == 'true'
     env: